Nearly a generation ago, MSNBC's Chris Matthews coined a description of our two political parties that may turn out to be his most enduring contribution to American punditry. Republicans, Matthews wrote, were the "Daddy Party," all about military security and self-reliance; Democrats were the "Mommy Party," all about health, education and nurturing.

At the time, in 1991, Democrats weren't sure they considered that much of a compliment. Since then, a long line of Democratic presidential candidates — including one who is an actual mommy, Hillary Rodham Clinton — have taken pains to prove they could be as tough and decisive as any stereotypical Mad Man.

But this year, facing an uphill battle to retain their majority in the Senate, the Democrats have decided to embrace the label as a badge of honor, making a strong appeal to women — especially working mothers — with whom Republicans have struggled to connect.

Democratic campaign rhetoric this year bristles with female-friendly ideas. The party hasn't merely reprised its long-standing endorsement of abortion rights; it's also calling for pay equity for women, stronger protections for pregnant women in the workforce, broader paid sick leave and family leave measures, and universal early childhood education.

Are any of those ideas likely to move forward in a bitterly divided Congress that's already turned from legislating to electioneering? Not a chance. But passing new laws isn't the point. The point is to send a message to female voters — especially unmarried women and working mothers — that the Democrats are on their side.

"When women succeed, America succeeds" was one of President Obama's applause lines in his State of the Union address, and he's repeated it frequently since. This spring, Obama plans to host a Working Families Summit at the White House to promote many of the same ideas.

And Democratic candidates aren't shy about using their gender as an asset. Alison Lundergan Grimes, the likely Democratic candidate for Senate Republican Leader Mitch McConnell's seat in Kentucky, told the Washington Post last week : "When I put ... my heels on, it's about kicking butt for the people of this state, especially the women."

Democrats have long cast themselves as champions of women's rights, especially reproductive rights. But the unabashedly woman-centric emphasis of this year's campaign is unusual, and largely based on electoral arithmetic.

Democratic strategists have calculated that if unmarried women vote in great numbers, the Democrats are likely to retain their majority in the Senate. If unmarried women stay home, Republicans will probably win the six seats they need to take over.

In midterm congressional elections, unlike presidential elections, winners are more likely to be determined by which voters turn out than by which party is more popular. In the 2008 presidential election, about 131 million people voted; in the 2010 congressional election, only 95 million voted — a drop-off of 36 million, or about 27%.

That drop-off meant the difference between a Democratic victory (in 2008) and a Republican triumph (in 2010). The voters who didn't show up, as is often the case in a congressional election year, were disproportionately Democratic, including millions of young people, minority voters and unmarried women.

Democrats are particularly targeting unmarried women (including single mothers) because they are the largest contingent, accounting for more than 10 million "drop-off voters," according to Lake. They're easier to find and to mobilize than young voters, she said. And they're important in every state; minority voters "aren't going to help much in Alaska or Montana," she notes.

The strategy isn't about persuading swing voters in the center to move; it's about convincing Democratic-leaning women who may be disappointed with the president, the economy and the healthcare plan that they should take the trouble to vote, even as they juggle jobs and child care.

Needless to say, Republicans aren't conceding the women's vote.

"Democrats are trying to create a narrative in which they're the only ones who care about women," said Katie Packer Gage, a former Mitt Romney aide. "Republicans care about women too. We just have a different way of making sure the economy is providing the jobs women need and that women have access to the healthcare they need."

GOP leaders have even organized a program, led by Packer Gage, to train candidates to frame their conservative message in a female-friendly way. It's designed partly to protect the party from the problem it ran into in 2012, when Rep. Todd Akin (R-Mo.), a candidate for the U.S. Senate, declared that women who were victims of "legitimate rape" could not become pregnant, and several other GOP candidates defended him.

Packer Gage said she couldn't guarantee that no Republican candidate would again wade awkwardly into reproductive issues. "There's always some knucklehead who makes a comment that the media gloms onto," she said. But next time, she asserts, GOP leaders will do a better job of containing the damage.

That may be a tall order. Democrats openly admit that they're praying for more gaffes from conservative candidates. "I loved Todd Akin," Lake chortled. Last month, when Steve Martin, an obscure Virginia state senator, referred to a pregnant woman as her child's "host," his comment instantly became fodder for Democratic fundraising pitches.